Methods and Apparatus for Updating Subsource Addressing Multicast Routing Records in a Communications Network

1. A method of facilitating subscription among at least two nodes in a distributed network, said method comprising the steps of: designating one of the nodes as a publisher node; designating one of the nodes as a subscriber node, wherein the subscriber node selects a subset of information using a predicate field; and, recording a path between the subscriber node and the publisher node, the path comprising at least one link between the subscriber node and the publisher node; said recording step comprising the step of recording each distinct link in the path between the subscriber node and the publisher node; said recording step comprising the step of recording each node in the path between the subscriber node and the publisher node, one node at a time; wherein a type of each node in the path is ascertained; and, wherein the nodes belong to a distributed multicast network.

2. The method according to claim 1 , wherein said step of recording a path comprises ascertaining whether any node is a fork node.

3. The method according to claim 1 , wherein said step of recording a path comprises ascertaining whether any intervening node is present in the path between the subscriber node and the publisher node.

4. The method according to claim 3 , wherein the distributed network includes at least one intervening node between the subscriber node and the publisher node, and further wherein: said step of recording a path comprises ascertaining whether any intervening node is a fork node.

5. The method according to claim 1 , wherein the distributed network includes at least three nodes, said method further comprising the steps of: designating one of the nodes as an additional subscriber node; and recording a path between the additional subscriber node and the publisher node, the path comprising at least one link between the additional subscriber node and the publisher node.

6. An apparatus for facilitating subscription among at least two nodes in a distributed network, said apparatus comprising: an arrangement for designating one of the nodes as a publisher node; an arrangement for designating one of the nodes as a subscriber node, wherein the subscriber node selects a subset of information using a predicate field; and, an arrangement for recording a path between the subscriber node and the publisher node, the path comprising at least one link between the subscriber node and the publisher node; said recording arrangement being adapted to record each distinct link in the path between the subscriber node and the publisher node; said recording step comprising recording each node in the path between the subscriber node and the publisher node, one node at a time; wherein a type of each node in the path is ascertained; and wherein the nodes belong to a distributed multicast network.

7. The apparatus according to claim 6 , wherein said recording arrangement is adapted to ascertain whether any node is a fork node.

8. The apparatus according to claim 6 , wherein said recording arrangement is adapted to ascertain whether any intervening node is present in the path between the subscriber node and the publisher node.

9. The apparatus according to claim 8 , wherein the distributed network includes at least one intervening node between the subscriber node and the publisher node, and further wherein: said recording arrangement is adapted to ascertain whether any intervening node is a fork node.

10. The apparatus according to claim 6 , wherein the distributed network includes at least three nodes, said apparatus further comprising: an arrangement for designating one of the nodes as an additional subscriber node; said recording arrangement being further adapted to record a path between the additional subscriber node and the publisher node, the path comprising at least one link between the additional subscriber node and the publisher node.

11. A computer readable medium readable by a computer, tangibly embodying a program of instructions executable by the computer to perform, method steps for facilitating subscription among at least two nodes in a distributed network, said method comprising the steps of: designating one of the nodes as a publisher node; designating one of the nodes as a subscriber node, wherein the subscriber node selects a subset of information using a predicate field; and recording a path between the subscriber node and the publisher node, the path comprising at least one link between the subscriber node and the publisher node; said recording step comprising the step of recording each distinct link in the path between the subscriber node and the publisher node; said recording step comprising the step of recording each node in the path between the subscriber node and the publisher node, one node at a time; wherein a type of each node in the path is ascertained; and wherein the nodes belong to a distributed multicast network.